Mechanical Properties of MiniBars™ Basalt Fiber-Reinforced Geopolymer Composites

Fly ash-based geopolymers represent a new material, which can be considered an alternative to ordinary Portland cement. MiniBars (TM) are basalt fiber composites, and they were used to reinforce the geopolymer matrix for the creation of unidirectional MiniBars (TM) reinforced geopolymer composites (MiniBars (TM) FRBCs). New materials were obtained by incorporating variable amount of MiniBars (TM) (0, 12.5, 25, 50, 75 vol.% MiniBars (TM)) in the geopolymer matrix. Geopolymers were prepared by mixing fly ash powder with Na2SiO3 and NaOH as alkaline activators. MiniBars (TM) FRBCs were cured at 70 degrees C for 48 h and tested for different mechanical properties. Optical microscopy and SEM were employed to investigate the fillers and MiniBars (TM) FRBC. MiniBars (TM) FRBC showed increasing mechanical properties by an increased addition of MiniBars (TM). The mechanical properties of MiniBars (TM) FRBC increased more than the geopolymer wtihout MiniBars (TM): the flexural strength > 11.59-25.97 times, the flexural modulus > 3.33-5.92 times, the tensile strength > 3.50-8.03 times, the tensile modulus > 1.12-1.30 times, and the force load at upper yield tensile strength > 4.18-7.27 times. SEM and optical microscopy analyses were performed on the fractured surface and section of MiniBars (TM) FRBC and confirmed a good geopolymer network around MiniBars (TM). Based on our results, MiniBars (TM) FRBC could be a very promising green material for buildings.